The present invention relates to electronic members designed on a premise that mutual electrical bonding of the electronic members (e.g., bonding of a semiconductor element and a circuit member) is performed. More particularly, it relates to an electronic part constituted by implementing the electronic members, and its implementation method. Hereinafter, such components as semiconductor elements and circuit members will be generically referred to as “electronic members”.
In recent years, there has been a significant increase in the request for the multi-function implementation, high-speed implementation, and light-thin-&-short-small implementation of electronic appliances which start with mobile appliances. What has become important in order to satisfy this request is the narrow-pitch implementation and low-back implementation of the electrode of an electronic appliance for inputting/outputting an electrical signal concerned.
Meanwhile, as is the case with the high-density implementation of an electronic appliance, an enhancement in the heat-liberation property becomes important. This is because there occurs an increase in the heat-liberation amount per unit area and volume. Also, simultaneously, the low-resistance implementation of the bonding portion becomes important in accompaniment with the decrease in the electrode's area.
As the bonding technologies for electrically bonding electrodes to each other among a plurality of electronic members, there are the ones such as electrically-conductive adhesive agent, soldering-used bonding, and metal's press bonding (i.e., bonding of gold bump or the like). Moreover, in contrast to these conventional bonding technologies, the following bonding technology is reported: Namely, in this technology, the use of silver-oxide particles makes it possible to embody a bonding portion having the heat-liberation and heat-resistant characteristics which are superior to those of the soldering and silver paste (refer to, e.g., “14th Symposium on Microjoining and Assembly Technology in Electronics”, Preprint Manuscript Collection, p. 185).
The bonding technology where the silver-oxide particles are used is the technology for reducing the silver-oxide particles to silver at a low temperature, thereby causing the bonding portion to be constituted with the low-resistance and high heat-liberation silver. What is used as its bonding material is a composition substance produced by mixing the silver-oxide particles with a reducing agent which allows the silver-oxide particles to be reduced at the low temperature. Also, the composition substance to be used is classified into a bonder-containing composition substance (JP-A-2003-309352) and a no-bonder-containing composition substance (JP-A-2007-335517). In particular, in the latter case where no-bonder-containing composition substance is used as the bonding material, a metallic bond can be obtained with respect to a partner electrode with which the bonding is to be performed (“14th Symposium on Microjoining and Assembly Technology in Electronics”, Preprint Manuscript Collection, p. 185). This metallic bond makes it possible to provide the bonding portion which has the excellent heat-liberation property.
Applying heat to the composition substance composed of the silver-oxide particles and the reducing agent results in the generation of silver particles whose particle diameter is small. These small-particle-diameter silver particles exhibit an excellent sintering capability even at the low temperature. Namely, organic components contained in the composition substance are decomposed by the heat-applying processing. This decomposition allows accomplishment of the sintering between the bonding of the generated silver particles and the electrode of an electronic part to be connected and the silver particles. Finally, the organic components are eliminated, which produces and completes the electronic part which has a bonding layer constituted with a metallic-silver network. The bonding layer constituted with the metallic silver results in implementation of the bonding layer which has the excellent heat-liberation characteristics. The heating temperature needed for the bonding is substantially equal to the one needed for the soldering materials widely used in the electronics implementations. Accordingly, attention has been focused on the silver-oxide particles as an electronic-part-use bonding material which is capable of the high heat-liberation. It is assumed, however, that the accomplishment of the satisfying-enough bonding state requires not only the heat-applying step to the bonding material, but also a pressure-applying step thereto.
Concerning the supply of the particle-like silver-oxide bonding material described above, the following techniques have been proposed: Namely, the supply should be performed in accordance with the following techniques with an addition of a reducing agent for reducing the silver oxide to silver at a low temperature.
1) technique whereby various solvents for viscosity adjustment are added to the bonding material, and the printing is performed in the resultant paste state.
2) technique whereby the bonding material is coated on a plate material in the paste state, and the resultant plate material is inserted.
3) technique whereby a reducing agent which will not fall into a liquid state at room temperature is selected, and a pressure is applied to the solid powder to insert the resultant sheet-shaped powder.